Cette citation est attribuée à Joseph Joubert, moraliste et essayiste français du XVIIIe siècle. Elle provient probablement de ses 'Carnets' ou 'Pensées', recueils posthumes publiés au XIXe siècle.
"Most men grow old within a small circle of ideas, which they have not drawn from their own depths. There are perhaps fewer false minds than sterile ones."